The present invention relates to a chromatography system, and in particular to a high throughput analytical chromatography system and method for operating the same to increase sample throughput and method development.
Separation science is a universal technique that benefits most scientists. Chromatographic separations provide a means to determine to what extent a reaction has yielded the desired products, to monitor impurities and dissolution profiles, and to study degradation pathways in drug products. Disadvantageously, chromatographic separations are relatively long and tedious processes with analysis times up to approximately 1 hour. Another problem associated with conventional chromatographic separations is the method development time. Screening multiple columns, materials and instruments to achieve optimum separation is labor intensive.
Heretofore, conventional analytical HPLC separation devices consist of a flow-metering pump to control volumetric flow rates of solvent gradients. Either low or high pressure mixing is used to produce the gradient. As the names imply, low pressure and high pressure mixing refer to the forming of the gradient either pre- or post-pump, respectively. To increase the capacity of the system it would be desirable to build an instrument capable of running several columns in parallel. For example, for parallel processing of 8 columns, 8 conventional detectors would be required and, depending on how the gradient is formed, either 8 or 16 pumps would be required for low pressure and high pressure mixing, respectively. The increased number of pumps and detectors necessary for this set up is costly and would take up a significant amount of space.
It is therefore desirable to develop a parallel processing chomatographic separation system that would be more cost effective, take up less space and be convenient and easy to use by the operator. As a result, the sample throughput time would increase as the method development time decreases.
For the purposes of the present invention the generic term high throughput high performance chromatography (HT-HPC) is defined to include high throughput high performance liquid, gas, capillary, microbore, preparative, electro, and supercritical fluid chromatography systems.
The present invention is directed to a HT-HPC system and method that solves the aforementioned problems and disadvantages associated with conventional serial systems and techniques.
The present invention is directed to a HT-HPC system that provides independent control of flow rates into an array of columns via flow control valves. Flow control valves are a convenient means to run multiple separations simultaneously, i.e., parallel processing, from common pressurized solvent reservoirs. The valves allow a manifold of columns to be analyzed in a high pressure mixing mode. The high pressure mixing mode advantageously lowers gradient dwell time and subsequently allows faster equilibration and analyses times.
In accordance with the present invention, the HT-HPC system and technique is more efficient in that it requires less analysis and method development time due to its parallel configuration. Accordingly, the system and method in accordance with the invention can produce results in a shorter period of time because multiple samples can be run in the same period of time as a single sample using a conventional system.
Another advantage of the present invention HT-HPC system is the design of high pressure mixing for relatively low gradient dwell times.
The present invention is directed to a high throughput high performance chromatography system operating at a high mixing pressure including a plurality of pressurized solvent reservoirs, e.g., pumps, each maintaining an associated solvent at a substantially constant pressure. A plurality of flow control valves are connected downstream of the pressurized solvent reservoirs for controlling the flow rate of the solvent into each column. The number of pressurized solvent reservoirs equals the number of solvents. Accordingly, the system reduces the number of pressure solvent reservoirs required thereby saving money and space. Furthermore, the system increases sample throughput, accelerates method development and minimizes organic waste. In an alternative embodiment, instead of each valve being associated with a single column, a plurality of columns may be connected downstream of each valve to form an array, whereby the valves associated with a particular lane control the flow rate of the solvent into the columns associated with that lane. This adds another dimension to the separation capabilities of the instrument thereby providing a very flexible instrument for method development and sample throughput. Additional dimensions may be added to the system, as desired.
Another embodiment in accordance with the present invention provides a s-shaped sample detection cell for measuring absorbance of the sample. The cell includes a section of tubing connected to the flow stream via two tees. Fiber optics deliver the light to the cell and directs the transmitted light from the cell to the detector. A single detector may be used for all parallel processed channels thereby reducing the cost and saving space.
Still another embodiment discloses a method for using the high throughput high performance chromatography system described above. One or more solvents are maintained at a substantially constant pressure using an associated pressurized solvent reservoir. The flow rate of the solvent into respective columns is controlled using a flow control valve connected downstream of each pressurized solvent reservoir. The gradient of each column may be independently adjusted.